Woven structured fabric with crossing twill lines

Abstract

A woven fabric for use in a machine to produce a fiber web, such as a tissue fiber web. A paper side of the fabric has warp yarns and weft yarns interwoven in a weave pattern, and twill lines, each formed by neighboring warp yarn flotations. Each warp yarn flotation of the weave pattern that contributes to the formation of the twill lines passes over a first weft yarn, which passes over a first warp yarn that directly neighbors the warp yarn flotation on a first side and passes below a second warp yarn that directly neighbors the warp yarn flotation on a second side opposite the first side. The warp yarn flotation also passes over a second weft yarn that directly neighbors the first weft yarn, and the second weft yarn passes below the first warp yarn and over the second warp yarn.

Claims

1. A woven fabric for a paper making machine, the woven fabric comprising: a multiplicity of warp yarns and weft yarns interwoven with one another in a weave pattern, defining a machine direction and a cross machine direction, a paper side and a machine side of the fabric; said paper side being formed with said warp yarns and said weft yarns and said paper side having a plurality of twill lines, each formed by a plurality of neighboring warp yarn flotations; each of said warp yarn flotations of said weave pattern that contributes to a formation of said twill lines passing over a first weft yarn; said first weft yarn passing over a first warp yarn that directly neighbors said warp yarn flotation on a first side and passes below a second warp yarn that directly neighbors said warp yarn flotation on a second side opposite the first side; said warp yarn flotation also passing over a second weft yarn that directly neighbors said first weft yarn; and said second weft yarn passing below said first warp yarn and over said second warp yarn.

2. The woven fabric according to claim 1, configured for producing a tissue fiber web.

3. The woven fabric according to claim 1, wherein said first weft yarn passes below said warp yarn flotation substantially in a center of said warp yarn flotation.

4. The woven fabric according to claim 1, wherein all weft yarns that pass below said warp yarn flotation also pass below either one or both of said first warp yarn and said second warp yarn.

5. The woven fabric according to claim 1, wherein all warp yarn flotations of the weave pattern that contribute to the formation of said twill lines have the same length.

6. The woven fabric according to claim 5, wherein the length of said warp yarn flotations is at least 5.

7. The woven fabric according to claim 6, wherein the length of said warp yarn flotations is 9.

8. The woven fabric according to claim 7, wherein the length of said warp yarn flotations is 10.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a partial view of a prior art woven fabric in a plan view onto the paper side of the fabric;

(2) FIG. 2 is a diagrammatic section taken along the weave line of one of the weft yarns in FIG. 1, along the cross machine direction;

(3) FIG. 3 shows a plan view on the paper side of a portion of a fabric according to a first embodiment of the present invention; and

(4) FIG. 4 shows a view on the paper side of a portion of a fabric according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(5) Referring now once more to the figures of the drawing in detail, a first embodiment of the present invention is shown in FIG. 3, which illustrates a view on the paper side of a portion of a woven fabric 10. The exemplary fabric is a forming fabric in a paper making machine and the fabric, or clothing, is suitable to form paper webs, such as tissue paper. The paper side, which is opposite the machine side, is formed by a plurality of warp yarns interwoven with a plurality of weft yarns. Since the woven fabric 10 is a single layer fabric the same warp yarns and weft yarns also form the machine side of the woven fabric 10. For the sake of clarity only three warp yarns are provided with reference signs, namely WA1, WA and WA2, and only two weft yarns are provided with reference signs, namely WE1, WE2. The fabric is flat woven meaning that the warp yarns extend substantially, but not all necessarily exactly, in machine direction MD of the woven fabric 10, whereas the weft yarns extend in cross machine direction CD of the woven fabric 10. The woven fabric 10 is made endless by a not shown seam. In case the fabric is not flat woven but round woven the warp yarns would correspond to the weft yarns and vice versa.

(6) Each warp yarn forms serval flotations, or floats, on the paper side of the woven fabric 10. The long flotations that have a length of 11 in this exemplary embodiment are referred to as warp yarn flotations in the following. Directly neighboring warp flotations form diagonal twill lines TL, or oblique twill lines TL, on the paper side of the fabric 10.

(7) One of these warp yarn flotations is designated with reference sign FL in FIG. 3. The warp yarn flotation FL is formed by warp yarn WA floating over eleven weft yarns. The middle one of these eleven weft yarns is referred to as first weft yarn WE1 in the following. The first weft yarn WE1 passes over a first warp yarn WA1 which first warp yarn WA1 directly neighbors the warp yarn WA that forms the warp yarn flotation FL on a first side, namely on the left-hand side in FIG. 3. Furthermore, the first weft yarn WE1 passes below a second warp yarn WA2 which second warp yarn WA2 directly neighbors the warp yarn WA that forms the warp yarn flotation FL on a second side, namely on the right-hand side in FIG. 3.

(8) The first weft yarn WE1 has a directly neighboring weft yarn which is referred to as second weft yarn WE2 in the following. Differently to the first weft yarn WE1, the second weft yarn WE2 passes below the first warp yarn WA1 and over the second warp yarn WA2.

(9) None of the weft yarns that pass below the warp yarn flotation FL passes above both, the first warp yarn WA1 and the second warp yarn WA2.

(10) FIG. 4 shows a view on the paper side of a portion of a woven fabric according to a second embodiment of the present invention. This embodiment is very similar to the first embodiment. The main difference is that the length of the warp yarn flotations that form diagonal twill lines is different. In this exemplary embodiment the length is ten, i.e., the respective warp yarns float above 10 weft yarns. Therefore, the same reference signs are used as in the first embodiment. With regard to the details of this second embodiment, reference is had to the description of the first embodiment which largely also applies to the second embodiment. The first weft yarn WE1 passes below the warp yarn flotation FL substantially at its center. In fact the precise middle would be between the first weft yarn WE1 and its directly neighboring second weft yarn WE2.

(11) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: 10 woven fabric 10′ woven fabric (prior art) CD cross machine direction FL warp yarn flotation FL′ warp yarn flotation (prior art) MD machine direction TL diagonal twill line TL′ twill line (prior art) WA1-WA2 first and second warp yarns WA1′-WA2′ first and second warp yarns (prior art) WA warp yarn (forming the warp yarn flotation FL) WA′ warp yarn (forming the warp yarn flotation FL′) (prior art) WE1-WE2 first and second weft yarns WE1′-WE5′ weft yarns (prior art)